1. Field of the Invention
The present invention relates to a body frame for vehicles. Priority is claimed on Japanese Patent Application No. 2003-001136, filed Jan. 7, 2003, the content of which is incorporated herein by reference.
2. Description of the Related Art
In a known vehicle body structure, concave portions called “beads” are provided at an end portion of the front frame, so that when a compressive load is imposed on the front frame, buckling of the front frame is controlled in a manner such that the front frame buckles from the concave portions (refer to Japanese Unexamined Patent Application, First Publication No. Hei 07-165110).
In the above known structure, the strength of the frame member itself is decreased due to the concave portions; thus, the size of the frame member should be increased so as to secure necessary strength, thereby increasing the weight of the vehicle. Additionally, in such a passive control in which concave portions are provided at the frame member, impact deceleration produced at the start of buckling is increased. In other words, high impact deceleration is produced even in a low-speed crash.